Sprayers comprising a turbine which, through ducts, distributes the air flow to various points generating different spraying areas to allow acting on a crop from various positions, enhancing the application of the treatment, are well known and widely used.
Examples of this type of sprayers can be found in French patent FR2727829, where a turbine generates an air flow directed towards a box with a plurality of ports from which the secondary ducts emerge.
French patent FR2887119 also relates to a sprayer with multiple ports and outlets at different heights.
None of the cited patents appear to mention the presence of an air flow control at the ports, the secondary ducts or the outlets, nor the possibility of opening or closing same.
Another relevant document is patent EP1810568 relating to a sprayer with a plurality of ports at different heights comprising a deflector that divides the distributor in two, such that depending on the position of said deflector air will reach all ports or only those of the distributor area to which the air flow is directed.
A more recent document is EP2193709, which relates to a sprayer where the presence of excess air inside the sprayer is prevented by regulating the air flow generated using a circular seal that limits the entry of air into the suction duct that feeds the turbine.
However, the air flow generated is not always directly proportional to the greater or lesser opening of the suction duct, as reducing the suction duct can result in a vacuum being created that affects the expected operating conditions of the turbine, potentially leading to overloads, material fatigue or increased consumption, among other consequences.
Thus, if in order to control the outlet flow the air outlet is closed, completely or partially, and the inlet is not changed, there is an uncontrolled air return that affects the control of the outlet flow and the sprayer, as it is required to work in improper conditions and withstand inadequate loads.
If alternatively the air inlet is limited reducing the turbine suction duct, a vacuum is generated that can damage the sprayer as it will not be operating in the conditions for which it was designed.